Cross Connection

A cross connection is a connection or arrangement of piping or appurtenances through which backflow of non-potable water could flow into the potable drinking water supply. Backflow is defined as water of questionable quality, wastes, or other contaminants entering a potable water supply system due to a reversal of flow. Whenever there is a physical connection between a potable water system and a non-potable environment, backflow may occur from backsiphonage or backpressure. These pressure fluctuations can be caused by hydrant flushing, a water main break, a power outage, or several other factors. In order to ensure safe drinking water, backflow prevention devices or assemblies are required at all connections where the water may be exposed to a pollutant or contaminant.

Our Cross Connection Unit has a State-approved comprehensive program designed for the inspection, elimination and prevention of cross connections at all service connections including commercial, industrial and residential sites. Our staff performs these inspections, which are included in your water rates, at a minimum interval of once every one-to-10 years. If our staff finds an unprotected cross connection, the customer will be notified by mail. This letter may provide a notice to install a proper backflow prevention device or assembly or have the existing one properly installed and/or tested by a licensed and certified tester. Any repairs, installation and/or testing are the responsibility of the homeowner or business. Many backflow prevention assemblies are required to be tested (WRC test form) annually in order to ensure they are working properly. These backflow prevention assemblies have internal seals, springs and moving parts that are subject to fouling, wear or fatigue and must be maintained in proper working order.

There are many simple things each of us can do to help prevent cross connections in and around our homes or places of business. Become familiar with your water piping system. Review every water connection in the building and visualize the result if the water flow reversed. Install the necessary backflow prevention devices or assemblies and keep them maintained, tested and in proper working order.

Several examples of typical water connections to review for proper protection are garden hoses, toilets or toilet fill valves, lawn sprinkler systems, laundry tubs, swimming pools, hot tubs, boiler systems, water assisted sump pumps and fire sprinkler systems. Common hazards associated with garden hoses include the misuse of the garden hose; leaving the end of the hose submerged in swimming pools, attached to chemical sprayers or laying on the ground. Without the proper backflow prevention device or assembly these garden hoses can expose the water supply to cesspools, pesticides or garden chemicals and animal feces. If not properly protected against backflow, these water connections may cause polluted and/or contaminated water to enter the potable water supply. This can result in illness and even death.

In addition, private wells that are also connected to the potable water supply are a direct cross connection and prohibited. The piping from a well must be permanently disconnected from the potable water supply. The well may still be used as a secondary source of water if it is not in any way connected to the public drinking water supply.

Learn more about safe drinking water. Can you help Prevent a Cross Connection?

Comparison shop! Contact several companies and ask for a quote over the phone. See our WRC Backflow Prevention Assembly Tester List.

Some items to ask when contacting a company to perform the installation/repair and/or testing:

• Do you charge a "trip" fee (a site visit fee)?
• What is the charge to test the assembly?
• What if my assembly fails, do you charge an additional fee if it needs service for items such as spider webs, dirt or to replace a seal?
• What is the charge if the assembly needs significant repairs or to be rebuilt? Is there a charge to retest my assembly after it's been serviced and/or repaired?
• What is the charge to install a new assembly and is testing included in that price?
• Is a permit from my municipality required and is there a fee involved?
• Is the tester a licensed plumber and ASSE 5110 certified?

*This information is provided as a courtesy and is not intended as an endorsement or referral. The businesses provided on this website have no affiliation with the Oakland County Water Resources Commissioner's Office. You are responsible for any and all services rendered by your contractor/plumber.

All completed backflow prevention assembly test results must be submitted online by your tester. Test results will no longer be accepted via email, fax or mail.

Search for a complete list of ASSE 5110 certified professionals by state, certification, or last name.

Search for a complete list of licensed master plumbers, journeyman plumbers or apprentice plumbers by state, license number or last name.